import java.util.ArrayList;
import java.util.Arrays;

public class Test2 {
    public static void main(String[] args) {
        String str1 = "welcome to bit";
        String str2 = "come";
        ArrayList<Character> arrayList = new ArrayList<>();
        for (int i = 0; i < str1.length(); i++) {
            if (!str2.contains(str1.charAt(i)+"")){
                arrayList.add(str1.charAt(i));
            }
        }

        for (char c:arrayList) {
            System.out.print(c);
        }
    }

}
